Up to this point, Ukraine has fought a purely defensive effort. They have done so with more success than any, including myself, expected. British intelligence reported on Sunday that up to one-third of the Russian forces that entered Ukraine have been destroyed. Ukrainian troops thwarted and then repulsed a Russian drive on Kyiv. They have mostly held the line in the Battle of Donbas so far, inflicting egregious losses on the Russian Army. An army on the defensive, however, cannot win back territory. It has to transition to the offense. How to Win the War If Kyiv has hopes of...